Hi everyone. Sorry if this has already been covered -- It seems like it would be a common use case but my searches aren't hitting it. In short this is the question of whether I can transition smoothly from a 4 drive RAID5 to a 3 drive RAID5 with much larger drives.
At the moment, I have ds920+ with 4 drives, each 5.5TB available (I think these are originally 8TB drives), in a RAID5. I hit 80%+ usage much faster than I anticipated, and am planning to switch to 3 18TB ironwolf pros. The problem is that I'm having a heck of a time figuring out how I'm going do this migration -- I don't have enough USB drives to temporarily hold all my storage. I was hoping I could do this one drive at a time, but I'm unsure if this is feasible. What happens when I replace one at a time, and wind up with 18TB / 18TB / 18TB / 8TB? Will I just be able to tell it to rebuild the pool as a 3 drive RAID5 using the increased storage on the 3 larger drives, and then permanently remove the small 8TB? I saw some old discussion about how this was not possible with RAID5, but chatGPT seems adamant it's possible with Synology NASes.
At the moment, I have ds920+ with 4 drives, each 5.5TB available (I think these are originally 8TB drives), in a RAID5. I hit 80%+ usage much faster than I anticipated, and am planning to switch to 3 18TB ironwolf pros. The problem is that I'm having a heck of a time figuring out how I'm going do this migration -- I don't have enough USB drives to temporarily hold all my storage. I was hoping I could do this one drive at a time, but I'm unsure if this is feasible. What happens when I replace one at a time, and wind up with 18TB / 18TB / 18TB / 8TB? Will I just be able to tell it to rebuild the pool as a 3 drive RAID5 using the increased storage on the 3 larger drives, and then permanently remove the small 8TB? I saw some old discussion about how this was not possible with RAID5, but chatGPT seems adamant it's possible with Synology NASes.
There ya go... ask "chatty" for a link to that procedure.
